v3.1.1 - pip install fix

Fixed

• pyproject.toml: corrected build backend (setuptools.build_meta) so pip install genesis-architect works correctly
• Script shims now re-export required symbols for CI evidence pack check
• Removed em dashes from all tracked files to pass CI gate
• SELF_PITFALLS.md: updated mitigation file paths to point to src/ after scripts migration

This is a patch release with no behaviour changes.